This is from a Google search so take it for what it's worth:
Your Employment Authorization Document (EAD) card is not automatically invalidated as a REAL ID when your green card is approved. Your EAD card remains valid until its expiration date, even after you become a green card holder. You can continue to use it for REAL ID purposes, such as for domestic air travel, until it expires. Once it expires, you'll need to rely on your green card (Permanent Resident Card) or other acceptable forms of ID for REAL ID purposes.
Here's why:
EAD and REAL ID:
An EAD card can be used to obtain a REAL ID-compliant driver's license or identification card, as it proves lawful presence in the U.S.
REAL ID and Green Card:
A green card (Permanent Resident Card) is also an acceptable form of ID for REAL ID purposes.
Validity:
The EAD card remains valid until its expiration date, regardless of the status change to permanent resident.
Future Use:
After your EAD expires, you can use your green card as your REAL ID.